BAGHDAD — It was billed as a national “dialogue” that would bring Iraq’s disparate and warring factions together to discuss their differences and emerge with a blueprint for peaceful coexistence.

But if the national reconciliation conference held here on Tuesday revealed anything, it was that the deep political and religious fissures that run through this battered country are nowhere close to healing.

Three of the most important political blocs boycotted the conference.

Few, if any, prominent Baathists, militia members or representatives of the insurgency — the groups that many believe represent the largest obstacles to reconciliation — showed up at the meeting.

And a prominent tribal leader stormed out of the auditorium after the opening speeches and threatened to leave the conference altogether.

“People want answers from us,” said Sheik Ali Hatem al-Suleiman of Anbar Province, a leader in the Awakening movement, the largely Sunni Muslim militia that has turned against the insurgency. “We’re not going to sit here only to listen to speeches.”

American and Iraqi government officials have insisted that reduced violence will pave the way for harmony and an end to sectarian strife. Prime Minister Nuri Kamal al-Maliki, speaking to the several hundred sheiks, clerics and politicians, Sunni and Shiite, who gathered in the auditorium of a heavily guarded convention center in the Green Zone, echoed this hope.

National reconciliation, he said, is “not just a political slogan” but “a safe boat” that would lead Iraq to stability, rebuilding the country’s infrastructure on a strong foundation.

But in interviews after the morning session, some who attended wondered how it was possible to have a dialogue with opponents who were absent.

“We were hoping to see more people invited, people who really represent the Iraqi components,” said Sheik Muhammad Fahman al-Rikahis, leader of the Shiite tribe Al Shibil in the south. “So the question is, why wasn’t everyone invited?”

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Former Prime Minister Ayad Allawi’s party, the Iraqi Consensus Front, refused to attend the meeting, as did Hiwar, a minority party that includes Shiites and Sunnis, and Tawafiq, the largest Sunni political bloc.

Ayad al-Samurai, a spokesman for Tawafiq, said that although some members had received personal invitations to the conference, no official invitation had been received, and “therefore its members preferred not to participate.”

But Akram al-Hakim, whose Ministry for National Dialogue organized the conference, insisted in a news conference on Tuesday that, despite rumors “in the media” that some political blocs had not been invited, invitations had been sent “to the blocs directly and to the heads of blocs, too.”

Few participants interviewed could even agree on who was to blame for the rifts that every day tear new wounds in an already bloodied country. Some blamed Mr. Maliki’s government, others the insurgents. Still others pointed to Baathists loyal to Saddam Hussein, or pointed to Iran, which they said exercised a strong influence over the government and some Shiite militias.

Vice President Dick Cheney, who was visiting Iraq on Tuesday, spoke at Balad Air Base, north of Baghdad, of “incredible progress on the ground in Iraq.”

Mr. Cheney also traveled to the semiautonomous Kurdish region, where he asked for President Massoud Barzani’s help to “conclude a new strategic relationship between the United States and Iraq, as well as to pass crucial pieces of national legislation in the months ahead.”

More than 300 miles to the south, in the Shiite holy city of Karbala, blood still covered the walls of buildings where a bomb exploded Monday, killing at least 43 people. Family members placed the bodies in coffins and traveled to Najaf to bury them, chanting, “God is great, God is great.”

In the northern city of Mosul, a car bomb exploded, killing three people and wounding 40.

A version of this article appears in print on , on Page A8 of the New York edition with the headline: Reconciliation Conference Highlights Iraq’s Deep Political and Religious Fissures. Order Reprints|Today's Paper|Subscribe